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UNIX Tools 2006 – Lecture 1

Explore the vast realm of UNIX tools in this lecture, covering operating system fundamentals, utilities, scripting languages, programming tools, administration, security, and networking. Discover the history, evolution, impact, and key players in the UNIX ecosystem. Join us to delve into the technical strengths, liberal licensing, open-source movement, current landscape, and the battle between UNIX and Linux.

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UNIX Tools 2006 – Lecture 1

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  1. UNIX Tools 2006 – Lecture 1 Jeffrey KornErnest Lee

  2. What will we cover? • Operating system overview • UNIX utilities • Scripting languages • Programming tools • Administration • Security • Networking

  3. Schedule • Lectures Wednesdays 7-9 with short break • Midterm: In class 10/25 • Final: In class 12/13 • Project due after final • Office Hour: Before class

  4. Who cares, how do I get an A? • Assignments: 30% • Project: 35% • Midterm: 15% • Final: 20%

  5. Books

  6. Available Free Online http://proquest.safaribooksonline.com

  7. Recommended Books

  8. Use the Web! • Wikipedia: http://wikipedia.org • http://google.com/linux

  9. Administrivia • Make sure you have an account • Sign up for the mailing list • Check the website regularly: CS homepage -> Course Home Pages -> G22.2245-001http://cs.nyu.edu/courses/fall06/G22.2245-001/index.htm • TAs: To be announced in 2 weeks • Assignment 0 is due before class next week

  10. Cheating • Don’t

  11. Cheating • Don’t • Seriously, don’t

  12. Our Heroes Ken Thompson Dennis Ritchie

  13. Video Games Spark Innovation PDP-7 Space Pilot

  14. In the Beginning • UNICS: 1969 – PDP-7 minicomputer • PDP-7 goes away, rewritten on PDP-11 to “help patent lawyers” • V1: 1971 • V3: 1973 (pipes, C language) • V6: 1976 (rewritten in C, base for BSD) • V7: 1979 (Licensed, portable) PDP-11

  15. Big Reason for V6 Success

  16. Derivative Systems • PWB, MERT • BSD: Adds many important features (networking, job control). • AT&T enters the computer business with System III, V

  17. Commercial Success • AIX • SunOS, Solaris • Ultrix, Digital Unix • HP-UX • Irix • UnixWare -> Novell -> SCO -> Caldera ->SCO • Xenix: -> SCO • Standardization (Posix, X/Open)

  18. …But Then The Feuding Began • Unix International vs. Open Software Foundation (to compete with desktop PCs) • Battle of the Window Managers Openlook Motif • Threat of Windows NT resolves battle with CDE

  19. Send in the Clones • Linux • Written in 1991 by Linus Torvalds • Most popular UNIX variant • Free with GNU license • BSD Lite • FreeBSD (1993, focus on PCs) • NetBSD (1993, focus on portability) • OpenBSD (1996, focus on security) • Free with BSD license • Development less centralized

  20. Today: Unix is Big

  21. Popular Success!

  22. The Score

  23. The Score

  24. Matrix Reloaded

  25. Some Desktop Success

  26. Linux at Google & Elsewhere

  27. Darwin • Apple abandoned old Mac OS for UNIX • Purchased NeXT in December 1996 • Unveiled in 2000 • Based on 4.4BSD-Lite • Aqua UI written over Darwin • Open Source

  28. Why did UNIX succeed? • Technical strengths! • Research, not commercial • PDP-11 was popular with an unusable OS • AT&T’s legal concerns • Not allowed to enter computer business but needed to write software to help with switches • Licensed cheaply or free

  29. The Open Source Movement • Has fueled much growth in UNIX • Keeps up with pace of change • More users, developers • More platforms, betterperformance, better code • Many vendors switching to Linux

  30. SCO vs. Linux • Jan 2002: SCO releases Ancient Unix : BSD style licensing of V5/V6/V7/32V/System III • March 2003: SCO sues IBM for $3 billion. Alleges contributions to Linux come from proprietary licensed code • AIX is based on System V r4, now owned by SCO • Aug 2003: Evidence released • Code traced to Ancient UNIX • Isn’t in 90% of all running Linux distributions • Already dropped from Linux in July • Aug 2005: Linux Kernel Code May Have Been in SCO Does Linux borrow from ancient UNIX or System V R4?

  31. UNIX vs. Linux

  32. Linux Distributions • Slackware – the original • Debian – collaboration of volunteers • Red Hat / Fedora – commerical success • Ubuntu – currently most popular, based on Debian. Focus on desktop • Gentoo – portability • Knoppix – live distribution

  33. In the 90’s, Thompson/Ritchie developed Plan 9 which applied UNIX ideas to distributed systems • Plan 9 evolved into Inferno, used for set top boxes • Lucent had problems, many people left • Thompson retired, now at startup • Ritchie still at Lucent

  34. The UNIX Philosophy • Small is beautiful • Easy to understand • Easy to maintain • More efficient • Better for reuse • Make each program do one thing well • More complex functionality by combining programs • Make every program a filter

  35. The UNIX Philosophy ..continued • Portability over efficiency • Most efficient implementation is rarely portable • Portability better for rapidly changing hardware • Use flat ASCII files • Common, simple file format (yesterday’s XML) • Example of portability over efficiency • Reusable code • Good programmers write good code;great programmers borrow good code

  36. The UNIX Philosophy ..continued • Scripting increases leverage and portability print $(who | awk '{print $1}' | sort | uniq) | sed 's/ /,/g' List the logins of a system’s users on a single line. • Build prototypes quickly (high level interpreted languages) 9,176 lines

  37. The UNIX Philosophy ..continued • Avoid captive interfaces • The user of a program isn’t always human • Look nice, but code is big and ugly • Problems with scale • Silence is golden • Only report if something is wrong • Think hierarchically

  38. UNIX Highlights / Contributions • Portability (variety of hardware; C implementation) • Hierarchical file system; the file abstraction • Multitasking and multiuser capability for minicomputer • Inter-process communication • Pipes: output of one programmed fed into input of another • Software tools • Development tools • Scripting languages • TCP/IP

  39. The Operating System • The government of your computer • Kernel: Performs critical system functions and interacts with the hardware • Systems utilities: Programs and libraries that provide various functions through systems calls to the kernel

  40. Kernel Basics • The kernel is … • a program loaded into memory during the boot process, and always stays in physical memory. • responsible for managing CPU and memory for processes, managing file systems, and interacting with devices.

  41. UNIX Structural Layout utilities shell scripts User Space C programs system calls compilers signal handler scheduler Kernel device drivers swapper terminal printer Devices disk RAM

  42. Kernel Subsystems • Process management • Schedule processes to run on CPU • Inter-process communication (IPC) • Memory management • Virtual memory • Paging and swapping • I/O system • File system • Device drivers • Buffer cache

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